gh-dashed-claude-marketplace-plugins-jj/SKILL.md

name, description

name	description
jj	Jujutsu (jj) version control system - a Git-compatible VCS with novel features. Use when working with jj repositories, managing stacked/dependent commits, needing automatic rebasing with first-class conflict handling, using revsets to select commits, or wanting enhanced Git workflows. Triggers on mentions of 'jj', 'jujutsu', change IDs, operation log, or jj-specific commands.

Jujutsu (jj) Version Control System

Overview

Jujutsu is a powerful Git-compatible version control system that combines ideas from Git, Mercurial, Darcs, and adds novel features. It uses Git repositories as a storage backend, making it fully interoperable with existing Git tooling.

Key differentiators from Git:

• Working copy is automatically committed (no staging area)
• Conflicts can be committed and resolved later
• Automatic rebasing of descendants when commits change
• Operation log enables easy undo of any operation
• Revsets provide powerful commit selection
• Change IDs stay stable across rewrites (unlike commit hashes)

When to Use This Skill

• User mentions "jj", "jujutsu", or "jujutsu vcs"
• Working with stacked/dependent commits
• Questions about change IDs vs commit IDs
• Revset queries for selecting commits
• Conflict resolution workflows in jj
• Git interoperability with jj
• Operation log, undo, or redo operations
• History rewriting (squash, split, rebase, diffedit)
• Bookmark management (jj's equivalent of branches)

Key Concepts

Working Copy as a Commit

In jj, the working copy is always a commit. Changes are automatically snapshotted:

# No need for 'git add' - changes are tracked automatically
jj status        # Shows working copy state
jj diff          # Shows changes in working copy commit

Change ID vs Commit ID

• Change ID: Stable identifier that persists across rewrites (e.g., kntqzsqt)
• Commit ID: Hash that changes when commit is rewritten (e.g., 5d39e19d)

Always prefer change IDs when referring to commits in commands.

No Staging Area

Instead of staging, use these patterns:

• jj split - Split working copy into multiple commits
• jj squash -i - Interactively move changes to parent
• Direct editing with jj diffedit

First-Class Conflicts

Conflicts are recorded in commits, not blocking operations:

jj rebase -s X -d Y     # Succeeds even with conflicts
jj log                   # Shows conflicted commits with ×
jj new <conflicted>      # Work on top of conflict
# Edit files to resolve, then:
jj squash                # Move resolution into parent

Operation Log

Every operation is recorded and can be undone:

jj op log                # View operation history
jj undo                  # Undo last operation
jj op restore <op-id>    # Restore to specific operation

Essential Commands

Command	Description	Git Equivalent
jj git clone <url>	Clone a Git repository	git clone
jj git init	Initialize new repo	git init
jj status / jj st	Show working copy status	git status
jj log	Show commit history	git log --graph
jj diff	Show changes	git diff
jj new	Create new empty commit	-
jj describe / jj desc	Edit commit message	git commit --amend (msg only)
jj edit <rev>	Edit existing commit	git checkout + amend
jj squash	Move changes to parent	git commit --amend
jj split	Split commit in two	git add -p + multiple commits
jj rebase	Move commits	git rebase
jj bookmark / jj b	Manage bookmarks	git branch
jj git fetch	Fetch from remote	git fetch
jj git push	Push to remote	git push
jj undo	Undo last operation	git reflog + reset
jj file annotate	Show line origins	git blame

Common Workflows

Starting a New Change

# Working copy changes are auto-committed
# When ready to start fresh work:
jj new                    # Create new commit on top
jj describe -m "message"  # Set description
# Or combine:
jj new -m "Start feature X"

Editing a Previous Commit

# Option 1: Edit in place
jj edit <change-id>       # Make working copy edit that commit
# Make changes, they're auto-committed
jj new                    # Return to working on new changes

# Option 2: Squash changes into parent
jj squash                 # Move all changes to parent
jj squash -i              # Interactively select changes
jj squash <file>          # Move specific file

Rebasing Commits

# Rebase current branch onto main
jj rebase -d main

# Rebase specific revision and descendants
jj rebase -s <rev> -d <destination>

# Rebase only specific revisions (not descendants)
jj rebase -r <rev> -d <destination>

# Insert commit between others
jj rebase -r X -A Y       # Insert X after Y
jj rebase -r X -B Y       # Insert X before Y

Working with Bookmarks (Branches)

jj bookmark list          # List bookmarks
jj bookmark create <name> # Create at current commit
jj bookmark set <name>    # Move bookmark to current commit
jj bookmark delete <name> # Delete bookmark
jj bookmark track <name>@<remote>  # Track remote bookmark

Pushing Changes

# Push specific bookmark
jj git push --bookmark <name>

# Push change by creating auto-named bookmark
jj git push --change <change-id>

# Push all bookmarks
jj git push --all

Resolving Conflicts

# After a rebase creates conflicts:
jj log                    # Find conflicted commit (marked with ×)
jj new <conflicted>       # Create commit on top
# Edit files to resolve conflicts
jj squash                 # Move resolution into conflicted commit

# Or use external merge tool:
jj resolve                # Opens merge tool for each conflict

Undoing Mistakes

jj undo                   # Undo last operation
jj op log                 # View operation history
jj op restore <op-id>     # Restore to specific state

# View repo at past operation
jj --at-op=<op-id> log

Revsets Quick Reference

Revsets select commits using a functional language:

Expression	Description
@	Working copy commit
@-	Parent of working copy
x-	Parents of x
x+	Children of x
::x	Ancestors of x (inclusive)
x::	Descendants of x (inclusive)
x..y	Ancestors of y not in ancestors of x
x::y	Commits between x and y (DAG path)
bookmarks()	All bookmark targets
trunk()	Main branch (main/master)
mine()	Commits by current user
conflicts()	Commits with conflicts
description(text)	Commits with matching description

Examples:

jj log -r '@::'           # Working copy and descendants
jj log -r 'trunk()..@'    # Commits between trunk and working copy
jj log -r 'mine() & ::@'  # My commits in working copy ancestry
jj rebase -s 'roots(trunk()..@)' -d trunk()  # Rebase branch onto trunk

Git Interoperability

Colocated Repositories

By default, jj git clone and jj git init create colocated repos where both jj and git commands work:

jj git clone <url>        # Creates colocated repo (default)
jj git clone --no-colocate <url>  # Non-colocated (jj only)

Using Git Commands

In colocated repos, Git changes are auto-imported. For non-colocated:

jj git import             # Import changes from Git
jj git export             # Export changes to Git

Converting Existing Git Repo

cd existing-git-repo
jj git init --colocate    # Add jj to existing Git repo

Configuration

Edit config with jj config edit --user:

[user]
name = "Your Name"
email = "your@email.com"

[ui]
default-command = "log"   # Run 'jj log' when no command given
diff-editor = ":builtin"  # Or "meld", "kdiff3", etc.

[revset-aliases]
'wip' = 'description(exact:"") & mine()'  # Custom revset alias

Advanced Topics

For comprehensive documentation, see:

• references/revsets.md - Complete revset reference
• references/commands.md - Full command reference
• references/git-comparison.md - Git to jj command mapping

Troubleshooting

"Working copy is dirty" - Never happens in jj! Working copy is always a commit.

Conflicts after rebase - Normal in jj. Conflicts are recorded, resolve when convenient.

Lost commits - Use jj op log to find when commits existed, then jj op restore.

Divergent changes - Same change ID, different commits. Usually from concurrent edits:

jj log                    # Shows divergent commits
jj abandon <unwanted>     # Remove one version

Immutable commit error - Can't modify trunk/tagged commits by default:

jj --ignore-immutable <command>  # Override protection